This application presents a plan for moving and then maintaining the Data Coordinating Center (DCC) for the Sleep Heart Health Study (SHHS) within the Center for Clinical Trials and the Departments of Epidemiology and Biostatistics of the Johns Hopkins University School of Hygiene and Public Health. The SHHS was started in 1994 as a multicenter prospective cohort study of the cardiovascular consequences of sleep-disordered breathing (SDB). During its initial five years, the SHHS investigators have completed overnight sleep studies (polysomnography) at home for 6,440 persons, enrolled through multiple clinical centers across the United States. During the five years (corresponding to Years 6-10 of funding for the SHHS) covered by this application for a DCC, the SHHS will continue follow-up of the participants with collection of a second PSG and extension of follow-up by five additional years. In addition to the monitoring of the additional data collection and the management of the data, the DCC will have responsibility for continuing cross-sectional analysis of the already collected data and for implementing longitudinal analyses, drawing on the already collected data from the parent cohorts and from the data collected during follow-up of the SHHS participants. State-of-art methods for longitudinal analysis will be needed to test the primary hypotheses of the SHHS. To meet these challenges, a multidisciplinary team will be assembled to staff the DCC, including expertise in pulmonary and sleep medicine, epidemiology, biostatistics, and data collection and management. The specific tasks to be carried out include: 1) a smooth transfer of data and operations from the current DCC to the new DCC; 2) continued support of data collection by the SHHS clinical centers through monitoring of the data collection process and of data quality; 3) maintaining and extending the SHHS data management system in order to assure efficient archiving of high quality data and the development of analytic databases for use by the DCC and the clinical centers; 4) development of an analytic plan, in conjunction with the Steering Committee, for longitudinal analyses, including the use of pre-existing data from the parent studies; 5) development and implementation of a plan for coordination of data collection and analyses with the Sleep Reading Center; 6) provision of logistical support to the SHHS investigators, including the coordination of meetings and conference calls, the tracking of publications, and other SHHS activities and; 7) working with the Steering Committee, to establish arrangements for distributed analyses, with replication by the DCC when appropriate, and for providing biostatistical consultation to writing groups, as needed.